| Characteristics | |
| Number of patients | 52 |
| Women | 17 |
| Median (range) age (years) | 68 (22–89) |
| Men | 35 |
| Median (range) age (years) | 61 (41–86) |
| Malignant disease (n = 33) | |
| Mesothelioma | 14* |
| Adenocarcinoma | 13 |
| Lymphoma | 2 |
| Small cell lung carcinoma | 2 |
| Squamous cell lung carcinoma | 1 |
| Bronchogenic carcinoma (radiological diagnosis only) | 1 |
| Benign disease (n = 19) | |
| Congestive cardiac failure | 6 |
| Benign pleural fibrosis | 7 |
| Parapneumonic effusion | 2 |
| Tuberculous pleuritis | 2 |
| Benign asbestos-related effusion | 1 |
| Constrictive pericarditis | 1 |
*12 cases of mesothelioma were diagnosed histocytologically; the remaining 2 were diagnosed on clinical and radiological follow-up with a history of asbestos exposure.